Distributor cap



' Dec. 15, 1936. J, L ARTHUR'i 2,064,052

DISTRIBUTOR CAP Original File d larch 3, 1930 gwmntov -.u- 1--r STATES QJHJIZ DISTRIBUTOR GA! James L. Arthur, Anderson, ma,

Illignor meme assignments. to General 1mm cm ration, Detroit, Mich, a corporation of Dela- Application March a, 1m. Serial m. in:

RenewedMaylO, 1m

1: Claims. (01. m- -ie) This invention relates to improvements in terminal heads particularly adapted to be used in the distributor unit of ignition systems for internal combustion engines. I

. s It is among the objects of the present invention to provide a terminal head of an ignition device in which condensed vapors are substantially prevented from causing short circuits between any of the terminals thereon. p

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawing wherein a preferred embodiment of one form of the present invention is clearly 15 shown.

In the drawing: v Fig. 1 is a'top plan view of a terminal head for an ignition device.

Fig. 2 is a flat sectional view taken along the line 22 of Fig. l.

Fig. 3 is an inverted plan view of the distributor head. I

Fig. 4- is a fragmentary sectional view taken through the center of the distributor head along the line 4 of Fig. l.

Fig. 5 is a fragmentary detail sectional view taken along the llneH of Fig. 2. Fig. 6 is a fragmentary sectional view taken along the line 6-6 of Fig, 3.

Fig. 7 is a fragmentary sectional view taken intermittently connects'the central terminal with the respective other terminals in proper sequence thereby to distribute impulses from the ignition to the various'engine spark plugs."

Ignitiongdevices of this type, if provided with a flat,- interior surface from which the terminals extend, may have these terminals short circulted by the formation of a him of moisture or con-- 55 densed vapor, thus rendering the device ineifecthrough the center of the distributor head along tive properly to distribute the sparking to the cylinders oh the engine.

Applicant gua agains a contingency by providing h s distributor cap f head with a sulcated, interior surface from his tera minals extend. The sulcated surfach provides intervening furrows between the various. terminals, said furrows substantially preventli igthe formation of a complete fllm of moisture or condensed vapor between terminals. The furrows 10 form alternate grooves and ridges. which, if of sufficient depth, will substantially prevent the moisture from creeping along the sides of the furrows to their bottom, thus a dry area is provided in the bottomof each furrow which acts is as a barrier to the short circuiting of thesparkim lses. 2 Referring to the drawing, the numeral 20 designates the distributor cap or head, made up of any suitable insulating material, preferably of 20 a condensation product such as bakelite orthe like. This distributor headcarries a plurality of terminals, 2| designating the central terminal about which the other terminals 22 are arranged impulse I in a circular row equally spaced from each other. 5

receiving any suitable means by which the cap is secured to the ignition device; As shown in Fig. l, these recesses v 23' are intennediate two terminals 22.

The inner surface of the distributor cap 20 is sulcated, presenting a plurality of annular wedgeshaped furrows designated by the numerals II, 28 and 21. As shown in thc'enlarged view in Fig. 8,

the furrows are wedge-shaped. being greater in saidte'rminais; thereby effecting the operation of the device detrimentallyi "In the present instance. however, the furrows will not permit such a conducting'iilm to be completed, for, as shown in Fig. 8, the vapors represented bythe small circles 28 will gather on the-ridges formed by the furrows and more particularly adjacent 5o the crest ofthe ridges. moisture or conalong the wall of the furrow to the extreme bottom of said furrow, thus there will be provided a comparatively dry area in the furrow designated by the numeral 29 which provides a barrier or an insulating area against the short circuitlng of the terminals.

In order to prevent completion of a conducting moisture film between the adjacent terminals 22, applicant has provided radial furrows, two of which, 30 and 3i, are diametrically opposite and extend from the central terminal outwardly to the inner surface of the annular wall of the cupshaped distributor cap, as shown in Figs. 2 and 3. It will be noted that radial furrows 30 and Ii cut across the annular furrows 25, 26 and 2], thus again presenting an impedance against undue accumulation of moisture on the annular ridges formed by the annular furrows mentioned. Such undue accumulation might result, if the ignition device is being operated at an angle in which one portion of the distributor cap or head 20 is considerably lower than the other portion. Radial furrows at rightangles to the radial furrows 30 and 3! as shown in Fig. 3 would terminate in the rounded portions 35 of the inner wall adjacent the recess 23 provided in the outer surface of the terminal cap. In order to eliminate this and to have furrows which reach substantially to the outer annular wall of the terminal cap, applicant has provided v-shaped furrows comprising converging branch portions 36, 31 and "a, 31a. adjacent the rounded portions 35. A radial furrow ll leads from the central terminal 2| and communicates with the furrow comprising branch portions 36 and 31 on the one side, while a similar radial furrow 39 leads from the central terminal 2| and communicates with the opposite furrow comprising branch portions "a and 310-, so that another impedance to the accumulation of condensed moisture in the annular furrows about the central terminal 21 is presented. It may be seen that the radial furrows SI and SI and the V-shaped furrows comprising arms 30,31 and 36a, 31a will substantially prevent condensed moisture from forming a continued film between might be adopted, all coming within the scope.

of the claims which follow.

What is claimed is as follows:

1. A terminal head for an ignition distributor comprising, a body of insulating material; a central terminal in said body, a plurality of spaced terminals in said body, arranged in a circular row about the central terminal; annular furrows-in cular row about the central terminal; annular furrows in the one surface of the body, substantially concentric with the central terminal; and furrows extending radially across the annular furrows and between adjacent terminals arranged in a circular row.

3. A terminal cap for an ignition device comprising a cup-shaped member of insulating material; diametrically opposite recesses in its outer surface; a central terminal exposed interiorly of the cup-shaped member; a plurality of terminals equi-spaced and arranged in a circular row about said'central terminal, and so that each aforementioned recess is positioned between two of these terminals; annular furrows in the inner surface of the cup-shaped member, substantially concentric with the central terminal; two oppositely disposed, radial furrows in said surface of the cup-shaped member, extending from the central terminal substantially to the outer annular wall of the cup-shaped member; a furrow in said surface of the cup-shaped member, adjacent each recess in its outer surface, each furrow comprising converging branch portions; and a radial furrow leading from theapex of the converging branch portions of each of said lastmentionedfurrows, across the annular furrows to the-central terminal.

4. A terminal cap for an ignition device comprising a cup-shaped member of insulating material, a central terminal exposed interiorly of the cup-shaped member; a plurality of terminals equi-spaced and arranged in a circular row about said central terminal; a series of circumferential furrows arranged within said cup-shaped member, spaced apart and interposed between said central terminal and the circular row of terminals: a plurality of radial furrows extending from the central terminal to the outer annular wall of said cup-shaped member, each of said radial furrows being spaced and interposed between successive terminals arranged in the circular row.

5. A terminal cap for an ignition device comprising, a cup-shaped body of insulating material;- a central terminal in said body; a plurality spacedterminalsinsaidbodyarrangedina' ular row about the central terminal; a series of circumferential projections arranged within said body spaced apart and interposed between said central terminal and the circular row of terminals. the edge of each successive projection following the projection nearest the'central terminal extending below the edge, of the preceding projection; and a plurality of radial recesses extending from the central terminal to the outer wall of said cup-shaped member, said recessesbeingarrsngedsothatarecessislocated between succesive terminals arranged in the circular row.

6. A terminal support comprising a body of insulating material and.having extending from one side thereof a plurality of separated terminals to which electrical conductors are adapted to be connected, means for preventing the formation by condensation of a continuous film of liquid on the surface of the insulating material between the terminals, said means comprising a. plurality of V-shaped grooves between the terminals of such depth that the condensate will not fill the grooves.

7. A terminal support comprising a body-of insulating material and having extending from one side thereof a plurality of separated terminals to which electrical conductors are adapted to be connected, means for preventing the formstionbycondensstionofscontinuousnhnofu liquid film between the terminals. 8. A terminal support comprising a body of liquid on the surface of the insulatingmaterial between the terminals, said means comprising a plurality of relatively deep and narrow grooves between the terminals, said grooves being of such a size and having such a ratio between depth and width that condensate will not cover the surface of such grooves sufiiciently to form a continuou insulating material and having extending from one side thereof a plurality of separated terminals to which electrical conductors are adapted to be connected, means for preventing theformation by condensation of a continuous film of liquid on the surface of the insulating material between the terminals, said means comprising a plurality of relatively deep and narrow grooves between the terminals and a series of sharp ridges separating the grooves, said grooves being of such a size and having such a ratio between depth and width that condensate will not cover the surface of such grooves sufficiently to form a continuous liquid film between the terminals.

9. A terminal support comprising a body of insulating material and having extending from one side thereof a central terminal and a plurality of spaced terminals arranged in a circular row about the central terminal and spaced therefrom, means for preventing the formation by condensation of a continuous. film of liquid on the surface of the insulating material between the terminals, said means comprising a plurality of relatively deep andtnarrow grooves extending around the central terminal and lying between said central terminal and the other terminals, and a series of sharp ridges separating said grooves, said grooves being of such a size and having such a ratio between depth and width that the condensate will collect on said ridges and will not cover the surface of said grooves sufliciently to form a continuous liquid film between the terminals.

10. A terminal support comprising a body of insulating material and having extending from one side thereof a central terminal and a plurality of spaced terminals arranged in a circular row about the central terminal and spaced therefrom, means for preventing the formation by condensation of a continuous film of liquid on the surface of the insulating material between the terminals, said means comprising a plurality of alternate grooves and ridges of V-shape extending around the central terminal and lying between said central terrninal and the other terminals, said grooves being of sufficient depth to prevent the condensate from covering the surface of said grooves sufiiciently to form a continuous film of liquid between the terminals.

ll. A terminal head for an ignition distributor comprising a body of insulating material, a central terminal in said body adapted to be connected to the ignition coil, a. plurality of spaced terminals in said bodyarranged in a circular row about the central lterminal and adapted to be connected to the spark plugs of an internal combustion engine, means for preventing the formation, by condensation, of a continuous film of liquid on the surface of said insulating material between the center terminal and the other terminals, said means comprising a plurality of relatively deep and narrow grooves extending around the center terminal and lying between the center terminal and said circular row of terminals, said grooves being of such size and having such a ratio of depth to width that the condensate will not cover the surface of the grooves sufficiently to form a continuous liquid film between the center and outer terminals.

12. A terminal head for an ignition distributor comprising a body of insulating material, a central terminal in said body adapted to be connected to the ignition coil, a plurality of spaced terminals in said body arranged in a circular row about the central terminal and adapted to be connected to the spark plugs of an internal combustion engine, means for preventing theformation, by condensation, of a continuous film of liquid on the surface of said insulating material between the center terminal and the other terminals, said means comprising a plurality of relatively deep and narrow V-shaped grooves ex- 

